Railway signaling



Aug. 30, 1938. R. A. M'cCANN RAILWAY S IGNALING Filed March e, 1956 2 Sheefis-Sheei 1 NQVNU NTOR .MQGanzz BY HIS ATTORNEY mvz Ronald A Aug. 30, 1938. MCCANN RAILWAY SIGNALING 2 Sheets-Sheet 2 Filed March 6, 1936 a mm Y ,4 L MNWMN E m. a I z .0 w H N QN L M T NNNQ k n NM. n 0 *NM Rb \H .3 Ll m aw MNHT N w w w Patented Aug. 30,

My invention relates particularly to signaling PATET OFFICE RAILWAY SIGNALING Ronald A. McCann,

Swissvale, Pa., assignor to -The Union Switch & Signal Company,

Swissvale, Pa., a corporation of Pennsylvania Application March 6,

19 Claims.

to railway signaling and involving wayside signals located along a trackway for governing the passage of trains.

The apparatus of this invention is an improvement over that disclosed in application Serial No. 26,784, of James J. Vanhorn, filed June 15, 1935,

for Railway signaling.

A feature of my invention is the provision of novel and improved apparatus for establishing a distinctive control for the rear of an occupied control is effective to cause of the associated wayside produced a three-block, of signaling.

I will describe one ing my invention, and

each of three sections in section. Each distinctive a corresponding aspect signal, whereby there is four-indication system form of apparatus embodywill then point out the novel features thereof in claims.

In the accompanying drawings, Figs.

are diagrammatic views which, when placed end to end in the order named, illustrate one form of apparatus embodying my invention.

Referring to the drawings, the reference characters 8.and 9 designate the rails of a stretch of railway track along which traffic normally moves by the arrows. These rails are divided by insulated joints [4 into a plurality of track sections or and Y-Z.

blocks W-X, X-Y,

Each track section is divided by insulated joints it into at least two sub-sections IT, 2T, 3T, 4T,

etc. circuit which includes Each sub-section is provided with a track a'track battery l5 connected across the rails at one end of the sub-section and a track relay, character TR with a designated by the reference prefix the same as the numerical prefix in the reference character of the associated sub-section, connected across the rails at the other end of the sub-section.

To govern the passage of trains through the tion. Each of these signals wayside signal, designated ter S with a suitable disis provided for each track seccomprises a top unit T and a lower unit L. These units may take any one of several forms of signal mechanisms such as semaphore, color light, Searchlight, or position light. As here shown, phore arm capable of each top unit is a semaassuming three positions and each lower unit is a semaphorearm capable of assuming two positions. has a horizontal or stop That is, the top arm position, a 45 or caution position, and a vertical or proceed position, and the lower arm has a horizontal or 1A and 1B 1936, Serial No. 67,467 (01. 246-50) stop position and a vertical or proceed position. Each semaphore arm assumes its horizontal position when deenergized.

Each section is provided with a direct current polarized signal control relay designated by the reference characters HD with a prefix the same as the prefix in the reference character of the associated signal.

Each section is also provided with an alternating current neutral signal control relay designated by the reference character H with a prefix the same as the prefix in the reference character of the associated signal.

Each direct current relay HD is connected to a two-wire line circuit over a back contact of the associated alternating current relay H, and the associated neutral alternating current relay H is connected to the sameline circuit through a condenser designated by the reference character Q with a prefix the same as the prefix in the reference character for the associated signal. It will be apparent, therefore, that the condenser Q will prevent the energization of the alternating current relay H by direct current and the contact of the alternating current relay H will prevent the energization of the direct current relay HD when the alternating current relay H is energized.

Each section is provided with an alternating current transfer relay designated by the reference character GP with a prefix the same as the prefix in the reference character of the associated signal, Each relay GP when energized is effective to sup- ;ply alternating current to the line circuit for the section next in rear and when deenergized is effective to supply direct current to that line circuit.

Operably connected to each top semaphore arm Tis a pole changer designated by the reference character P with a prefix the same as the prefix in the reference character for the associated signal. Each pole changer Poccupies its normal condition when the associated semaphore armis in its caution position or in its vertical position or at any point between thesetwo positions, and occupies its reverse condition when such arm is at any point below the caution position. Also operably connected to each top semaphore arm T is a contact l8-l8A closed only when the arm is in itscaution position and a contact 1 l9l9A which is closed when the arm is in its caution position or its vertical position or at any point between these two positions. Operably connected to each lower semaphore arm L is a contact 20-20A which is closed only when that arm is in its vertical position.

Each top semaphore arm T and each lower semaphore arm L is provided with a lamp TE and LE, respectively, for displaying supplementary color light indications corresponding to the position of the associated semaphore arm. The lamps TE and LE at each signal are controlled by an approach lighting relay designated by the reference character ER with a prefix the same as the prefix in the reference character of the associated signal; The approach lighting relay for each signal is in I,

alternating current the rectifier is effective to by-.

pass one-half of the alternating current wave so that the approach lighting relay is energized in one direction only and when the line circuit is energized with direct current the rectifier is disconnected from the shunt path around the approach lighting relay so that all of the direct current must pass through the relay. Referring to signal l 28, for example, it will be noted'that since relay IZGP is energized so that its front contact 62 becomes closed, the rectifier IZR 'will be effective for by-passing one-half of the alternating current wave. The approach lighting relay I ZER, therefore, will be energized in one direction and willinaintain its back contact 63 opened so that the lamps TE and LE for signal 125 will not become lighted. When relay [2GP is deenergized so that its front contact 62 becomes opened, the rectifier I 2R is no longer connected across the relay I2ER. Regardless of the polarity of the line circuit, therefore, relay IZER willbe energized by direct current so that its back contact 63 remains opened. When a train enters section W X so that the line circuit for that section becomes opened, thenrelay lZER will become released. When relay I-ZER is released so that its back contact 63 becomes closed, the lamps TE and LE of signal |2S will become lighted to provide a light indication corresponding to the indication displayed by the position of the semaphore arms. 7

For supplying the direct current and alternating current energy, each section is provided with a suitable source of direct current energy, the terminals of which are designated by the reference characters B and C; and each section is provided with a suitable source of alternating current energy, the terminals of which are designated by the reference characters BX and OK.

The manner in which the signals are controlled to cause the display of the different as pects will best be understood by tracing the circuits and explaining the operation of the appa ratus simultaneously.

A train K is here shown occupying the section immediately to the right of location Z so that the line circuit for the control of relays 141-1 and MI-ID is opened. c

Signal MS, therefore, is displaying both its semaphore arms T and 'L in the horizontal position to indicate stop.

With signal MS in this condition, pole changer :MP is occupying its reverse position and relay 3GP is deenergized.

The polarized direct current relay I'3HD is'energized in the reverse direction by a circuit which passes from terminal B of the source of direct current at signal HES, through contact 24 of pole changer MP, back point of contact 25 of relay MGP, front contact 26 of track relay 6TB, front contact 21 of track relay 5TB, relay Isl-ID, back contact'28 of alternating current relay I3H, front contact 29 of track relay 5TH, front contact 36 of track relay 6TB, approach lighting relay MER, back point of contact 3| of relay l lGP and contact 32 of pole changer MP to terminal of the same source of direct current.

Since relay I3HD is energized in the reverse direction, a caution circuit for the top semaphore arm T of the signal MS is energized by current which passes from terminal 13 through front contact 33 of relay l3I-ID and semaphore arm T tov terminal C. The signal I38, therefore, is displaying its top semaphore arm in the caution position and its lower semaphore arm in the horizontal position to indicate approach next signal prepared to stop. 7

The 'polarizeddirect current relay I2HD is energized in the normal direction by a circuit which passes from terminal 13, at signal I3S, through contact 38 of pole changer l3P, back point of contact 39 of relay I3GP, approach lighting relay I3ER, front contact 40 of relay 4TB, front contact 4! of relay 3TR, back contact 42 of relay 12H, relay IZHD, front contact 43 of relay 3TH, front contact 44 of relay 4TB, back point of contact Q of relay I3GP, and contact 46 of pole changer HP to terminal C.

Since relay i2HD is energized in the normal direction, the caution circuit for the top semaphore arm T of signal lZS is energized over front contact 41 of relay IZHD; and a clear circuit for the lower semaphore arm is energized by current which passes from terminal B through front contact 4? of relay EZHD, normal polarcontact Eliof relay lZHD, contact |8l8A of top semaphore arm T, and lower semaphore arm L to terminal C. The signal :28, therefore, is displaying its top semaphore arm in the caution position and its lower semaphore arm in the Vertical position to indicate approach next signal at medium speed.

The transfer relay I 2GP is energized over a circuit which passes from terminal BX of the source of alternating current, at signal IZS, H

through contact 28-20A of lower semaphore arm L of signal I 2S, contact Iii-49A of top semaphore arm T and relay lZGP to terminal CX of the same source of alternating current.

Since relay 'IEGP is energized, neutral alternating current relay H H is energized by alternating current over a circuit which passes from terminal BX, at signal 523 through front point of contact 50 of relay IZGP, approach lighting relay IZER, front contact 5! of relay ZTR, front contact;52 of relay lTR, relay Ill-I, condenser HQ, front contact 53 of relay ITR, front contact 54 of relay ZTR, and front point of contact 55 of relay I2GP to terminal CX.

Since relay HH is energized, both the caution circuit and the clear circuits for the top semaphore arm T of signal HS are energized over frontcontacts 5'? and 58, respectively, and since relay HHD is deenergized the lower semaphore arm L is deenergized because front contact 59 of relay HHD is opened. The signal HS, there circuit which passes from terminal BX through front contacts 60 of relay IIH, contact l9--l9A of'top semaphore arm T of signal HS and relay HGP to terminal OK. The line circuit for the section next in rear of signal HS, therefore, is supplied with alternating current so that the signal (not shown) for the section next in rear is displaying the proceed at normal speed indication.

When the train K vacates the section immediately to the right of location Z, the line circuit for the control of signal MS will be then supplied with direct current energy-in the reverse direction so that that signal will display its top semaphore arm in the caution position and its lower semaphore arm in the horizontal position to indicate approach next signal prepared to stop. When signal MS is in this condition, the line circuit for the control of signal |3S will be then energized by direct current of normal polarity so that signal will display'its top semaphore arm in the caution position and itslower semaphore arm in the vertical position to indicate approach next signal at medium speed. I

When signal ass is displaying this indication, relay l3GP'will become energized so that the line circuit for the control of signal IZS will be then supplied with alternating current energy over front points 39 and d5 of relay I3GP to cause signal Us to display the normal proceed indication.

It will be noted that in the event of the absence of the alternating current source of power the line circuits will be supplied with direct current so that signal indications will be provided to keep traffic moving. For example, if the alternating current source of power at signal IZS should fail, the transfer relay lZGP would become released so that direct current of normal polarity would be supplied to the line that signal would change its indication from proceed at normal speed to approach next signal at medium speed.

It will also be noted that but'two line wires are required between signals. I

It will be apparent, therefore, that the apparatus embodying my invention provides a simple, reliable and economical means for controlling a three-block, four-indication, system of signaling. Although I have herein shown and described only one form of apparatus embodying my invention, it is understoodthat various changes and modifications may be made therein within the scope of the'appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, two successive sections of railway track, a signal for the forward section having a first semaphore arm capable of assuming a caution position as well as'a vertical and a horizontal position, said signal also having a second semaphore arm capable of assuming a vertical and a horizontal position, means for causing said signal to assume its different positions in accordance with traffic conditions in advance of the signal, a contact closed when the first arm occupies either its caution or its vertical position, a contact closed when the second arm occupies its vertical position, a relay, a circuit for said relay including said two contacts, a pair of conductors including contacts. of said relay, and a signal for the rear ise tioncontrolled by said conductors.

circuit for signal HS and controlled by said circuit.

2. In combination, two successive sections of railway track, a signal for the forward section having a semaphore arm operable to diiferent positions, said semaphore arm normally occupying a vertical position, a normally energized relay for'controlling said signal in accordance with traffic conditions in advance of the signal, another relay, a circuit for said other relayincluding a front contact of said normally energized relay and a contact closed when the said semaphore arm occupies its vertical position, a circuit controlled by traffic conditions in said rear section, said circuit being supplied with alternating current when said other relay is energized and with direct current when said other relay is deenergized, an alternating current relay and a direct current relay both connected to said circuit, and a signal for the rear section controlled by said two relays.

- 3. In combination, two successive sections of railway track, a signal for the forward section having a first semaphore arm and a second semaphore arm, said first arm capable of assuming a caution position as well as a vertical and a horizontal position and said second arm capable of assuming a vertical and a horizontal position, means for controlling said signal in accordance with traflic conditions in advance of said section, a contact closed when the first arm occupies its caution position, a circuit for the second arm including said contact, another contact closed when the second arm occupies its vertical position, a relay, a circuit for said relay including said other contact, a circuit controlled by traffic conditions in said rear section, said circuit being controlled by said other relay, and a signal for the rear section controlled by said circuit.

4. In combination, two successive sections of railway track, a signal for the forward section, a source of alternating current, an alternating current relay which is deenergized when said signal displays certain indications and which is energized when said signal displays certain less restrictive indications provided said alternating current is present, a pole changer operably governed by said signal and connected to a source of direct current, a circuit which is connected to said pole changer when said relay is deenergized and which is connected to said source of alternating current when said relay is energized, said circuit being controlled by traffic conditions in said rear section, a direct current polarized relay and a neutral alternating current relay both controlled by said circuit, and a signal for the rear section controlled by said two relays.

5. In combination, two successive sections of railway track, a signal-for the forward section having a lamp and controlled by trafiic conditions in that. section, a pole changer controlled by said signal and connected to a source of direct current, a source of alternating current, a circuit for the rear section controlled by trafiic conditions in said section, a relay controlled by said pole changer or said source of alternating current, an approach lighting relay responsive to either direct current or alternating current and connected in said circuit for controlling said lamp, and signaling means for the rear section 6. In combination, a railway signal including a lamp, a circuit controlled by traffic conditions in rear of said signal, a direct current relay connected in said circuit for controlling said lamp, va sourceof direct current, a source of alternating current, a normally energized alternatingcurrent relay which becomes deenergized when-said alternating current source is absent, means including contacts of said alternating current relay for'su-pplying said circuit with either alternating current or direct current according as said alternating current relay is energized or deenergized respectively, and means including a rectifier for causing said direct current relay to become responsive to alternating current.

7. In combination, a section of railway track having a pair of conductors governed by traffic conditions in said section, a signal for said section capable of assuming several distinctive aspects, a direct current polarized relay and an alternating current neutral relay for jointly controlling the difierent aspects of said signal, said relays being supplied with current from said pair of conductors, and means selectively governed by traffic conditions in advance of said section for supplying direct current of one polarity or direct current of the other polarity or alternating current to said conductors but not both direct and alternating current simultaneously.

8. In combination, a section of railway track having a pair of conductors governed by trafiic conditions in said section, a polarized direct current relay and a neutral alternating current relay both receiving energy from said conductors, means selectively governed by trafiic conditions in advance of said section for supplying to said conductors direct current of normal polarity or direct current of reverse polarity or alternating current'but not both direct current and alternating current simultaneously, and traffic governing means for said'section controlled by said two relays.

9. In combination, a section of railway track, a pair of conductors governed by traffic conditions in said section, a direct current polarized relay and an alternating current neutral relay both receiving energy from said conductors, means governed by traific conditions in advance of said section for supplying either alternating current or direct current of one polarity or the other polarity but not both direct current and alternating current simultaneously to said conductors, means for preventing the energization of said direct current relay when said alternating current relay is energized, meansfor preventing the energization of said alternating current relay when said conductors are supplied with direct current, and a trafiic governing device controlled'by said two relays.

10. In combination, a section of railway track, a pair of conductors governed by traffic conditions in said section, a direct current relay and an alternating current relay both receiving energy from said conductors, means governed by trafiic conditions in advance of said section for supplying either alternating current or direct current but 'not both simultaneously to said conductors, means including a back contact of said alternating current relay for preventing the energization of said direct current relay when the alternating current relay is energized, means including a condenser for preventing the energization of said alternating current relay when said conductors are supplied with direct current, and traffic governing means controlled by said two relays.

11. In combination, a section of railway track, a pair of conductors governed by trafli'c conditions in said section, a signal for said section, a

direct current relay and an alternating current relay both for governing said signal, means including a condenser for connecting said alternating current relay to said conductors, means including a contact of said alternating current relay for connecting said direct current relay to said conductors, and means governed by trafiic conditions in advance of said section for supplying either alternating current or direct current to said conductors.

12. In combination, a section of railway track, a pair of conductors governed by traffic conditions in said section, a signal in advance of said section, a pole changer supplied with a source of direct current and operably connected to said signal, a relay which when energized supplies alternating current to said conductors and when deenergized connects said pole changer to said conductors, means for energizing or deenergizing said relay depending upon the condition of said signal, and signaling means for said section controlled by said conductors and selectively responsive to alternating current and direct current.

13. In combination, two successive sections of railway track each such section having a pair of conductors governed by traffic conditions in said section, a signal for the forward section controlled by the conductors for that section and capable of displaying four distinctive aspects including a proceed aspect and an approach medium aspect as well as an approach aspect and a stop aspect, a relay which is energized when said signal is displaying either the proceed or the approach medium aspect and which is deenergized when said signal is displaying either the approach or the stop aspect, means controlled by said relay according as said relay'is energized or deenergized for supplying alternating current or direct current to the pair of conductors for the rear section, an alternating current relay and a direct current relay both connected to said conductors for the rear section, and a signal for the rear section co-ntrolled'by said two relays.

14. A railwayrsignaling system comprising a stretch of track divided into sections each having a pair of conductors governed by trafiic conditions in said section, two relays for each section one polarized direct current relay and one neutral alternating current relay and both connected to the associated conductors, means controlled by said two relays for each section for selectively supplying to the conductors for the section next in rear direct current'only of normal polarity or direct current only of reverse polarity or for supplying alternating current only; and a signal for each section controlled by said two relays of that section and arranged to have a first aspect when both relays are deenergized, a second aspect when the direct current relay is energized reverse and the alternating curent relay is deenergized, a third aspect when the direct curent relay is energized normal and the alternating curernt relay is deenergized, and a fourth aspect when the direct curent relay is deenergized and the alternating current relay is energized.-

15. In combination, a section of railway track having a pair of conductors governed by traffic conditions in said section, a signal for each section, said signal having a first unit capable of displaying three diiferent conditions and a second unit capable of displaying two different conditions, a polarized direct current relay and a neutral alternating current relay energized from relay for nal, means responsive to traflic conditions in advance of said section for supplying said pair of conductors with direct current of normal or with direct current of reverse polarity or with alternating current, a circuit including a front contact of said direct current relay for causing said first unit to assume one condition, another circuit including a front contact of said alternating current relay also for causing said first unit to assume said one condition, a circuit including another front contact of said alternating current causing said first unit to assume a different condition and a circuit including a normal polar contact and a front contact of said polar ized relay for causing said second unit to assume one condition provided said first unit then occupies a particular condition.

16. In combination, a railway signal including a lamp, a circuit controlled by trafiic conditions in rear of said signal, a relay for controlling said lamp and connected in said circuit, a source of direct current, a source of alternating current, another relay controlled in accordance with trafiic conditions in advance of said signal for connecting said circuit to the direct current source or the alternating current source, a rectifier, and a shunt path across the winding of said one relay and including said rectifier as well as a contact of said other relay.

17. A railway signal system comprising a stretch of railway track divided into a plurality of track sections, a pair of conductors for each section governed by trafiic conditions in said section, a polarized direct current relay for each sec tion receiving energy from the associated conductors, an alternating current relay also receiving energy from the associated conductors, means controlled by the two relays for selectively supplying alternating current only or direct current only of one polarity or of the other polarity to the conductors for the section next in rear of the associated section whereby a distinctive control is efiected for each of three consecutive track sections next in rear of an occupied section.

18. In combination, a stretch of railway track divided into a plurality of successive block sections a pair of conductors for each section governed by trafiic conditions in said section, a signal for each section capable of assuming several different aspects, each signal having associated therewith a direct current polarized relay and an alternating current neutral relay jointly controlling the different aspects of said signal, said relays being supplied with energy from the pair of conductors for the section with which said signal is associated, and means controlled jointly by said relays for supplying direct current of one polarity or direct current of the other polarity or alternating current but not both direct and alternating current simultaneously to the pair of conductors for the adjacent block section in the rear of the section with which said relays are associated.

19. In combination, a stretch of railway track divided into a plurality of successive block sections each having associated therewith a pair of conductors governed by trafiic conditions in said section, a signal for each section capable of displaying a stop indication and a plurality of different proceed indications having varying degrees of speed restriction, each signal having associated therewith a direct current polarized relay and an alternating current neutral relay supplied with current from the pair of conductors for the section with which the signal is associated, said relays jointly controlling the signal with which they are associated and the supply of direct current of normal or reverse polarity and also jointly controlling the supply of alternating current to the pair of conductors for the adjacent block section in the rear, the control of the signal by the relays associated therewith being arranged in such a manner that the direct current relay alone is effective to condition the signal to display at least one of its restrictive proceed indications, whereby said signal will not be caused to display a stop indication as a result of the absence of alternating current.

RONALD A. MCCANN. 

